Tires are an important safety-related component because the tire/road contact patch largely determines the dynamic behavior of the vehicle. For instance, low tire pressure may cause unstable vehicle motion. Tire tread separation may lead to a variety of unstable vehicle motions, such as over-steer or under-steer. Abnormal tire wear may cause untrue driving performance. Tire imbalance can cause tire grip variation and varying stability. Thus, it is desirable to monitor the status of the vehicle tires.
However, most conventional tire monitoring systems only monitor tire pressure. Current tire pressure monitoring sensors have limited functionality, and are not capable of discerning coordinate acceleration data for a wheel. Conventional tire pressure sensors provide pressure and temperature sensing along with data processing and wireless communication of such data. Most also include a movement detection device such as switch or piezoelectric device that activates upon a radial acceleration. The movement detection devices “wake” the sensor to initiate data transmission, while saving battery life while the wheel is not moving.
Advanced tire monitoring sensors (ATMS) are currently being developed. Besides traditional pressure and temperature data, ATMS include coordinate acceleration data for the associated wheel. This is accomplished with micro-electro-mechanical systems (MEMS) accelerometers. Such devices have advantages in terms of robustness, and the ability to provide a linear output response to acceleration. Multiple MEMS are also contemplated to provide multi-axis (coordinate) acceleration data for the associated wheel.
ATMS provide the potential to vehicle manufacturers to offer new or enhanced capabilities in vehicle systems. The present disclosure is directed toward providing improved vehicle safety systems utilizing ATMS.